add assign_material_id in API reportActivity

app/Http/Controllers/AssignMaterialController.php

@@ -174,10 +174,10 @@ class AssignMaterialController extends Controller
 					->where('description', '=', $row->material_name)->first();
 				return $val_uom ? $val_uom->uom : null;
 			})
-			->addColumn('material_id', function($row){
-				$material_id =AssignMaterial::select('assign_material_to_activity.material_id')->join("m_req_material as m", "m.id", "=", "assign_material_to_activity.material_id")
+			->addColumn('assign_material_id', function($row){
+				$assignMaterial =AssignMaterial::select('assign_material_to_activity.id')->join("m_req_material as m", "m.id", "=", "assign_material_to_activity.material_id")
 				->where('activity_id', $row->activity_id)->where('m.description', $row->material_name)->first();
-				return $material_id ? $material_id->material_id : null;
+				return $assignMaterial ? $assignMaterial->id : null;
 			})
 			->addColumn('action', function($row){
 				$dataPlan = AssignMaterial::select('assign_material_to_activity.id')->join("m_req_material as m", "m.id", "=", "assign_material_to_activity.material_id")